Physics Department

You Sound Funny

You Sound Funny

In a physics demonstration (done carefully and safely), an instructor inhaled helium gas. When the instructor spoke their voice was at a very high pitch (frequency). Why did the pitch of their voice change?

A. Helium gas is lighter than air and therefore has a faster speed than air. This faster speed results in the higher pitch voice.

B. The Helium gas is less dense than air, and a vibrating, less dense material will produce a higher frequency than a vibrating dense material.

C. The Helium gas actually permeates the outer layer of the vocal cord muscles, increasing their flexibility and allowing the vocal cords to vibrate more quickly, resulting in a higher pitched sound .

D. The Helium absorbs moisture and the dryer gas produces the high pitch.